This invention relates to an occlusion device for the closure of physical apertures, such as vascular or septal apertures. More specifically, this invention relates to an occlusion device for the heart that centers itself in the defect to ensure that the defect is properly sealed.
The heart is generally comprised of four chambers: the left and right atrium, and the left and right ventricle. Separating the left and right sides of the heart are two walls, or septa. The wall between the two atria is the interatrial septum and the wall between the two ventricles is the interventricular septum. There are several defects which can affect the septa of both children and adults, including patent ductus arteriosus, patent foramen ovale, atrial septal defects (ASDs), and ventricular septal defects (VSDs). Although the causes and physical aspects of these defects vary by type, each of these defects is generally an aperture, flap, or hole, in the septum which allows blood to shunt between chambers in the heart where there is no blood flow in a normal, healthy heart. This abnormal shunt can cause a variety of health problems.
Normally, permanently repairing certain cardiac defects in adults and children requires open heart surgery, which is a risky, painful, and expensive procedure. Surgery for closure of a heart defect is major heart surgery, which requires the patient to undergo general anesthesia and opening of the chest cavity. The patient must spend several days in the hospital and thereafter may take several weeks to be able to return to normal levels of activity.
To avoid the risks and discomfort associated with open heart surgery, modern occlusion devices have been developed that are small, implantable devices capable of being delivered to the heart through a catheter. These devices effectively seal the defect but do not require surgery. Rather than surgery, a catheter inserted into a major blood vessel allows an occlusion device to be deployed at the defect once the device has been moved through the catheter to the treatment site. This procedure is performed in a cardiac cathlab and avoids the risks and pain associated with open heart surgery.
Modern occlusion devices can repair a wide range of cardiac defects, including patent foramen ovale, patent ductus arteriosus, atrial septal defects, ventricular septal defects, and may occlude other cardiac and non-cardiac apertures. One form of an occlusion device generally has a lower or left side, an upper or right side, and a center section. Once the occluder is deployed, the occluder's center section extends through the center of the defect. The left and right sides occlude the aperture on the respective sides of the patient's septum.
As mentioned, several types of septal defects exist. In addition, the size of defects varies from patient to patient. Some defects are larger than others. If the aperture is large, the center section of the occluder must remain in the center of the defect so that the left and right sides of the occluder occlude the entire aperture. If the center section moves or is not properly centered, the right and left sides follow the center and portions of the aperture may no longer be covered and thus, may be exposed. If portions of the aperture are exposed, blood may continue to shunt through the defect lessening the effectiveness of the occluder. Consequently, there is a need in the art for an occlusion device which has a centering system to keep the device properly centered.
This invention provides an occluder with a self centering system comprising a plurality of elastic rings that keeps the occluder properly centered in the defect. The self centering system allows the center of the occluder to remain properly positioned within the defect so that the left and right sides cover the entire aperture. Because the occluder remains properly positioned, the chance of blood shunting through the aperture is reduced and the effectiveness of the occluder is increased.